1. Field of the Invention
The present invention relates to an image pickup apparatus and a control method of the image pickup apparatus, in which a mechanical shutter and an electronic shutter are usable.
2. Description of the Related Art
Conventionally, in an image pickup apparatus such as a digital camera, a mechanical shutter in which an exposure time is controlled by mechanically driving shutter curtains (or shutter blades or the like) for shielding object light has been used.
By contrast, recently, an image pickup apparatus equipped with an image pickup mode by an electronic shutter which controls an exposure time by controlling reset timing and readout timing of an image pickup device has been proposed.
The electronic shutter is capable of reducing noise (no running sound and no running stop sound of a shutter is generated), improving continuous shooting performance (there is no need of reading an image data while maintaining a state of shielding light, and an exposure for a next frame starts immediately after the reading), and facilitating low power consumption (no electric power is needed for mechanical running of the shutter curtains or the like), etc. in comparison with the mechanical shutter.
Further, there has been proposed a technique of equipping the image pickup apparatus with both of the mechanical shutter and the electronic shutter, and using one of the mechanical shutter and the electronic shutter properly.
First, in the current general technique, since a curtain speed of the electronic shutter by rolling readout of a CMOS image sensor, for example, is considerably slower than a curtain speed of a mechanical shutter such as a focal plane shutter, an image of a moving object with large distortion is picked up in a case where the electric shutter is used in comparison with a case where the focal plane shutter is used. On the other hand, when the mechanical shutter is used, since a mechanical drive mechanism is to be operated, power consumption larger than that when the electronic shutter is used is required.
Therefore, for example, in Japanese Patent Laid-Open Publication No. 2013-179488, there is described a technique of detecting motion of an object and performing photographing using the electronic shutter when the motion of the object is small, and performing photographing using the mechanical shutter when the motion of the object is large. Thereby, it is made possible to reduce the distortion of the moving object and to facilitate low power consumption.